1. Field of the Invention
The present invention related to a 6-degree-of-freedom (6-DOF) travelling system, particularly provides as a bodily sensing machine like a flight simulator for training or amusement, that has a human-riding cage serving as a manipulated object in a certain space.
2. Related Art
A human-riding cage of a 6-DOF travelling system serving as a bodily sensing machine like a flight simulator for training or amusement has been manipulated by six serial links comprising six linear actuators like hydraulic cylinders, or manipulated by some parallel links driven by gears or so on. The serial link mechanism and the parallel link mechanism are disclosed in Japanese Patent Laid-Open Gazette No. Hei 9-285,988 as prior arts for manipulators, however, they have actually been used for driving the cage of the bodily sensing machine and the like.
The serial link mechanism and the parallel link mechanism have the problem that a floor of the cage supported by either of them becomes high, thereby requiring a stool for getting on and off the cage.
Furthermore, the system using the serial link mechanism is disadvantageous in that it cannot take a large space for driving the cage relative to the dimension and form thereof because the cylinders as the linear actuators are liable to interfere with one another, and in that it requires great energy or power to drive piston rods of the cylinders for executing the 6-DOF motion of the cage.
The parallel link mechanism also requires great energy to be driven because its moving parts are heavy. Furthermore, the working space is small and its travelling object sometimes becomes a singular point at the center of the working space, where the travelling object cannot generates force against external force.
It will now be proposed that a cage is suspended by a plurality of lines like wires or cables for solving the above-mentioned problem, in other words, for reduction of driving energy and for lowering the floor of the cage.
In this regard, the above document discloses a manipulator having a travelling plate, which is originally horizontal, disposed between upper and lower fixed plates and moved in six degrees of freedom by wires and spools driven by motors. However, the shown manipulation mechanism cannot be applied for construction of a bodily sensing machine even if the travelling plate is replaced with a human-riding cage.
For a 6-DOF travelling system using lines, there is a paper written by Satoshi Tadokoro, Shinsuke Nishioka, Tetsuya Kimura, Motofumi Hattori, Toshi Takamori and Kiyoshi Maeda in the title of xe2x80x9cOn Fundamental Design of Wire Configurations of Wire-Driven Parallel Manipulators with Redundancy, Proc. 1996 Japan-U.S.A. Symposium on Flexible Automation, Marriott Hotel at Copley Place, Boston, Mass., July 7-10, Vol. 1, pp. 151-158, 1996xe2x80x9d.
In this paper, there is a reference made to the effects of the redundancy caused by more than six, especially eight suspending lines. Furthermore, this paper advances the two best designs having eight suspending lines satisfying heuristics as follows: wires should suspend the travelling plate antagonistically to one another so as to apply tensions onto the plate in both opposite directions; the distance between wires and the center of gravity of the travelling plate should be long for applying moment effectively; wires are desirably longer for larger working space while being prevented from their contact with one another; there should be enough margin at one side of the travelling plate at least, where no wire crosses for prevent the wires from contact to end-effectors (later-discussed pulleys serving as fixed points) and the travelling object; and characteristics is desirably symmetric with respect to the approach axis of the end-effector.
One of the two designs (in the name of the T-type) is advantageous in wide rotation at most points, especially in the rotation round the z axis, and the other (in the name of the Rod-type) in translation. The T-type has such a configuration that two wires extend through one fixed point above the travelling plate to the front and rear ends of the travelling plate, and three wires extend in connection with the travelling plate through each of two fixed points disposed laterally symmetrically with respect to the travelling plate.
The object of the present invention is to provide a bodily sensing machine replacing that driven by serial or parallel links, wherein a human-riding cage can be sufficiently lowered for getting on and off, and is driven in six degrees of freedom by actuators whose moving portions are light, so as to reduce the driving cost and to make the cage widely rotate at most points.
To achieve the object, the bodily sensing machine according to the present invention comprises a human-riding cage; a plurality of, preferably, eight wires connected to the cage; an actuator hauling up and veering out each wire for varying the position and attitude of the cage, and a controller system controlling the tension of each wire without looseness, so as to drive the cage in six degrees of freedom.
Also, the present invention provides a 6-DOF travelling system such that a solid which is applicable to the cage is suspended and driven by eight lines in a certain space. The system serves as an application of the cited T-type plate travelling system using eight lines for construction of a bodily sensing system.
To achieve the object, the 6-DOF travelling system according to the present invention is provided with a solid serving as a travelling object which has eight connection points; eight lines hauled up and veered out in connection with the respective connection points of the solid; and three fixed points guiding the eight lines therethrough. Each of the three fixed points is equivalent to one point. The three fixed points consists of a top fixed point disposed above the solid; a right fixed point disposed rightward from the solid; and a left fixed point disposed leftward from the solid. The right and left fixed points are laterally-symmetrically disposed with respect to the solid when the solid is originally positioned.
The eight connection points of the solid consists of first-eighth connection points:
The first connection point and the second connection point are disposed forward and backward on the top of the solid. Two of the eight lines in connection with the respective first and second connection points are extended through the top fixed point.
The forward upper third connection point, the backward upper fourth connection point and the longitudinally-middle lower fifth connection point are disposed at rightward portions of the solid, so that the three rightward connection points are arranged so as to form a vertically-flapped isosceles triangle with the fifth connection point as the bottom vertex thereof. Three of the eight lines in connection with the respective third, fourth and fifth connection points are extended through the right fixed point.
The forward upper sixth connection point, the backward upper seventh connection point and the longitudinally-middle lower eighth connection point are disposed at leftward portions of the solid, so that the three leftward connection points are arranged so as to form a vertically-flapped isosceles triangle with the eighth connection point as the bottom vertex thereof, which is identical with the triangle shape made by the three rightward connection points. Three of the eight lines in connection with the respective sixth, seventh and eighth connection points are extended through the left fixed point.
The third and sixth connection points are arranged symmetrically with respect to the first connection point. The fourth and seventh connection points are arranged symmetrically with respect to the second connection point.
According to the present 6-DOF travelling system, any of the eight lines is varied in its length between corresponding one of the eight connection points and corresponding one of the three fixed points while being adjusted in its tension, thereby moving the solid in six degrees of freedom.
The solid of the above-mentioned 6-DOF travelling system has a longitudinally cylindrical body which is laterally-symmetrically polygonal, preferably, octagonal when viewed along the longitudinal direction of the solid. The octagonal cylindrical cage as an application of the solid matches with the contradictory requests: minimization of the entire thereof and widening of the inner space thereof.
The polygonal (octagonal) shape as the view of the solid taken along the longitudinal direction of the solid has a pair of originally-lateral top and bottom sides, so that the floor of the cage as an application of the solid is originally horizontal, thereby being comfortable for a rider.
The solid has a pair of originally-vertical front and rear surfaces in the polygonal shapes. The originally-lateral top side of the front surface is provided on its middle portion with the first connection point, on its right end with the third connection point and on its left end with the sixth connection point. The originally-lateral top side of the rear surface is provided on its middle portion with the second connection point, on its right end with the fourth connection point and on its left end with the seventh connection point.
Additionally, an edge joining the right ends of the originally-lateral bottom sides of the front and rear surfaces is provided on its middle portion with the fifth connection point, and an edge joining the left ends of the same bottom sides is provided on its middle portion with the eighth connection point.
Such a shape of the solid and such an arrangement of the lines suspending the solid enables the so lid to be widely rotated at most points. Hence, the 6-DOF travelling system is sufficiently appropriate to the above-mentioned bodily sensing machine.
Other and further objects, features and advantages of the present invention will appear more fully from the following description.